Dies at WOT OK at idle?

[Evinrude Trouble]

I have a J70LLCNB and i took it out for the first time today. I adjusted the idle like it was told earlier and it started right up and idled smoothly. I get past the no wake to try and see if i can get her to plane out and as soon as i try a hole shot the rpms jump like their suposed to and about 3 seconds later the motor sputters the RPMs slowly go down and the motor dies and has to be restarted. I tried easing the throttle forward and when i get about half way to WOT is when the engine starts to loose RPMs but if i pull throttle back to below half the rpms return to normal. I tried squeezing the primer bulb when the rpm's started going down and it did not make a difference. Any suggestions.

 

[tashasdaddy]

Re: Dies at WOT OK at idle?

link & sinc.

 

[ezeke]

Re: Dies at WOT OK at idle?

I think you might want to do another compression test and spark test and post results - sounds like you are dropping a cylinder.

Are you sure the spark advance is connected?

 

[HighTrim]

Re: Dies at WOT OK at idle?

When were the carbs last rebuilt? May be time for a bath and rebuild, followed by a link n sync as Tash said. Check to see if the timer base (starboard side, under the edge of the flywheel, linked to the throttle lever) moves smoothly without sticking when you advance the throttle.

Take the airbox cover off & observe whether the throttle plates are parallel.

Also, the timer base should start it's travel before the throttle plates start to open, or else she will die instantly when you try to accelerate.

 

[Evinrude Trouble]

Re: Dies at WOT OK at idle?

What is spark advance and how is it connected to the throttle linkage? How do i adjust/fix this problem? What is a timer base? I'm not very good at electrical/Ignition systems. From what i have read you need a timing light to do a link and sync which i do not know how to use or have for that matter. I dont think i'm dropping a cylinder but i dont have a compression tester. spark is good and the plugs look good. I have no idea how long its been since a carb rebuild but every time i have done a carb rebuild i always have problems. I have taken the air box off and the throttle plates all look parallel. When o throttle up it does not die instantly it dies slowly over a span of about 4 or 5 seconds. I know i should go out and buy a manual but i dont wana spend 30 bucks to use it for 10 min for this link and sync procedure. Is this link and sync procedure specific to each motor or is this a generic procedure that is done the same for all motors? Is there a place that i can get this link and sync procedure without having to buy the manual? I'm on a very limited budget and the wife says she does not want to hear the B word (boat) any more. Does anybody know how expensive the rebuild kits are for the carbs? Does this link and sync procedure take very long?
I really wana do this the right way but spend as little money as possible. I've come up with what i'm gonna name her once shes workin good "Das Boat" what do ya think?

 

[tashasdaddy]

Re: Dies at WOT OK at idle?

i don't have a manual, for that motor. you don't need timing light or any special tools. you just have to follow the step by step procedure, miss a step, start over from beginning. try the library, it may be in one of the after market manuals, libraries usually have them.

 

[HighTrim]

Re: Dies at WOT OK at idle?

I know i should go out and buy a manual but i dont wana spend 30 bucks to use it for 10 min for this link and sync procedure.

Trust me, you will use it much more than that. It will be the best 30 bucks you ever spent, and WILL pay for itself a million times over. It is very optimistic thinking however

 

[w2much]

Re: Dies at WOT OK at idle?

And from my recent experience. Check your anti syphon valve. My 150 was doing the exact same thing. The primer bulb stayed hard but felt spongy for some reason but no fuel was getting through the valve. Easy fix take it out and try it., but replace it when done. Good luck.